If player A (1200) has played 0 game, and plays against player B, (1200), who's played 10000 games, obviously if player A wins, he/she will gain hundreds of points (as you probably experienced when you first went on this site) and player B's rating will change a bit.
This makes sense if you consider probability intuitively, and the fact that player A is essentially unrated, and player B's rating is super established.
How is it possible to lose 156 rating points in one game, from 1672 to 1516, esp when playing someone less than 100 rating points below (Live Chess)? Plus, the opponent did not gain anywhere near that many rating points. BlackElo starts at 1590, goes up to 1600. (In the PGN & c. Wh starts at 1672, is reduced in one game to 1516--see below).
"Your new standard rating is 1516 (-156).
Match Scores: aisling42 (1516) [0.0] vs MASdeVera (1600) [1.0]"